A communication protocol can be a way of organizing a wireless conversation between a number of devices (e.g., access card, tag, reader, access device, etc.). For example, the communication protocol can include an air interface type (e.g., how the data is transferred, etc.), an access control (e.g., which device initiates the communication, etc.), and/or data definitions (e.g., type of data associated with a tag, interpretation of the data sent, etc.).
There are various protocols that use different approaches for the wireless conversation between devices. The various protocols typically require that a reader and a tag (e.g., access card, etc.) utilize the same communication protocol. If the communication protocol is not the same, the data to be sent may not be sent properly or not be sent at all.
The data to be sent can be a unique identifier (e.g., access data, electronic product code (EPC), etc.). The unique identifier can be verified by the reader to determine a number of characteristics of the data (e.g., type of card, issuer of the card, user of the card, etc.). A particular unique identifier can instruct a particular action of the reader. For example, a particular unique identifier can allow access to a restricted area by instructing the reader to unlock a door to the restricted area.